Differential amplifiers are used in a variety of applications, for example, in satellite receivers.
Satellites transmit either in the Ku or Ka band. The Ku band ranges from 12.2˜12.7 GHz, the Ka band from 18.3˜18.8 and 19.7˜20.2 GHz. The satellite dish receiver electronics consists first of a Low Noise Amplifier (LNA) followed by a Low Noise Block (LNB). The LNB comprises a mixer, filter and amplifier (also known as gainblock). The mixer of the LNB delivers the signal at an Intermediate Frequency (IF) in the band from 250 MHz to 750 MHz. After filtering, the still single-ended signal is input to a gainblock. The output of the gainblock goes to an analog-to-digital converter (ADC) after which the frequency shift of the channel and the combining is performed in the digital domain. The ADC operates on differential signals for reasons of improved signal-to-noise ratio. Consequently, a gainblock IC with differential outputs is an advantageous feature relative to current practice of using a gainblock with single-ended outputs with an external discrete balun making differential signals for the ADC.
A problem with known differential output stages is that they require a high driving signal and have insufficient linearity.